1. Field of the Invention
This invention relates generally to methods and apparatus for monitoring or controlling pests, and more particularly to the monitor or control of harmful social insects which live in colonies and are capable of communication through chemical signals, such as insects of the order Isoptera, and more specifically, termites.
2. Description of the Prior Art
There are presently available a number of methods and apparatus that may be utilized for monitor or control of harmful social insects. In general, such methods and apparatus are directed to controlling pests once they have been detected as a result of a monitoring procedure. After detection, the pests are controlled by inducing the pests to ingest or otherwise come into contact with a toxicant in a matrix which is attractive to pests, particularly pests from a specific nest or colony.
Subterranean termites typically dwell in soil and often form large colonies. Members of the colony forage for food and burrow galleries or passageways in the soil outwardly from the colony nest, and portions of food located by foraging termites are returned to the nest. Termites communicate the location of a food source to other termites within the colony by chemical signals such as pheromones. These characteristics may be exploited in the field of the present invention to effectively control pest infestations. In the course of traveling to the nest, an insect may leave highly specific trail pheromones which direct or recruit other insects to a food source. Subsequently, other insects, usually from the same colony, detect the chemical signal and are thus directed to that food source. The concentration and composition of these pheromones can be species and colony specific, and trail pheromones may be very different from feeding-initiating pheromones. Insects can leave feeding-initiating pheromones in a food source itself, communicating the desirability of the food. Deposit of specific pheromones in a toxicant-containing matrix food source by foraging insects aids in recruiting other nestmates to the toxicant-containing matrix, whereupon they forage, are exposed to toxicant, and deposit more pheromone, thus creating a cyclical control method. Toxicants to be delivered to insect populations are preferably slow-acting, lethal at concentrations which do not repel target insects, and capable of being combined with an insect food. Insects directly contacting or ingesting the toxicant will not be killed immediately, but will travel to their colony to recruit other nestmates to the toxicant, thereby resulting in the control of large numbers of colony members due to interactions with the colony before death occurs.
In providing methods and apparatus for monitoring of and delivery of toxicant to pests, it is advantageous to minimize disruption to a site where pests have begun feeding. Where such a site is located in the soil, site disruption is minimized, for instance, as described in PCT international publication 93/05004 and U.S. Pat. No. 5,329,726, by using a station housing which is permanently fixed into the soil and capable of being periodically refilled with replacement monitoring and toxicant-containing matrices.
Despite the availability of such methods and devices, there exists a need in the art for methods and apparatus for pest monitoring or control that are capable of use in above-ground applications where placement of an apparatus within a hole would be impractical, such as where pests are present in structures, trees, and the like, and which provides a stable, minimally disrupted site where it is possible to have the replenishment of toxicant-containing matrix with the ability to restrict exposure to such matrix by pest control personnel.